Tundra sources

http://www.blueplanetbiomes.org/ I trust this one because it ends in org this stands for orginization this prooves that its an actual company.
http://www.ownbox.com/rr/nationalgeographi.com I trust this website because I know national georaphic it's famous for this kind of project.
http://www.bbc.co.uk/nature/life/Polar_Bear I trust this website because it's the bbc if someone copies it they'll get fined.
http://www.bbc.co.uk/nature/lifeI trust this website because it's the bbc if someone copies it they'll get fined.
http://www.ehow.com/info_8060835_foods-tundra.html I trust it because it ends in html.
http://thetundra.weebly.com/threats.html I trust this becase it ends in html.
http://www.blueplanetbiomes.org/tundra_animal_page.htm I trust this because it ends in html.